Strange noise from car....

kenfyoozed

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1967 Chrysler 300 fast top, 440 engine. It seems to run ok. I think I may have a heat soak issue with the edelbrock 1411 carb, but going to address that soon with a carb kit and a spacer. Hopefully that helps, but under hard acceleration I get this clatter..... I can't for the life of me figure out where its coming from. It sounds like its more toward the rear of the car. While in park I can rev the engine and it doesn't happen. At first I was thinking it was the pistons but since it doesn't do it while in park that would lead me to think its more transmission issues. The trans doesn't feel like its slipping when this happens, as the car continues to pull hard. So i thought maybe its something in the exhaust... but again it doesn't do it when its in park. So what am I dealing with?
 
I'd say spark knock from your symptoms, but if you say it is coming from the rear, maybe there is something loose in your exhaust. Slide under and bang on the pipes, see if it make noise.
 
It is louder in the rear but it comes from under the car somewhere. It only happens during driving while trying to hard accelerate. Easing on the throttle, driving normally, no issues. But if you punch the throttle for it to take off it starts rattling or knocking. If it were spark knock how does one fix that?
 
Im a new when it comes to auto engines. Wrenching on powersport engines for a while but the automobile engines intimidate me at first and I have a lot to learn so I appreciate everyones patience. In my searching I was wondering if my timing should be adjusted. Ive never done this so Im off to learn how to do this as well. And I promise I am not beating on her. She's my cruiser but when i need to pass someone or move quickly she start rattling and I back off immediately.
 
Im a new when it comes to auto engines. Wrenching on powersport engines for a while but the automobile engines intimidate me at first and I have a lot to learn so I appreciate everyones patience. In my searching I was wondering if my timing should be adjusted. Ive never done this so Im off to learn how to do this as well. And I promise I am not beating on her. She's my cruiser but when i need to pass someone or move quickly she start rattling and I back off immediately.
Quick question what do you mean by rear, rear of engine or rear end of car? Does sound like a timing issue. Get yourself a good timing light and get to know how you use it.
 
A dry, failing u-joint can produce a rattle/clatter, but more typically that sort of death-rattle noise is preceded for some time by a high-pitched, undulating squeal. Anyway, they're under the car and and one of them is "towards the rear"
 
A muffler with a bad baffle or other parts loose inside can also make a lot of noise. Try shaking the mufflers to see if you can make them rattle. Usually a muffler that has internal parts running around is at the point of failure and the outer casing will show some swelling or other signs of distress.

Dave
 
Checked the timing the best I know how at this point so Ill describe what I did... Hooked the timing light to the battery and the #1 cylinder,diver side front spark plug wire. Started engine, idles at about 575-600rpm. Shine the light on the degree marks on the from of the engine and it was before the 10* mark. I then realized I had a button on my timing light that would change the degrees. I pressed it until it read 11* and was dead on at the 0*mark on the engine. I then had my son raise the rpm to 3500 and I adjusted the light again until it was back on 0* at the engine and the timing light read 36*. I did the same thing but this time disconnected the vacuum hose from the carb to the distributor and got the same results 36*. Did I do this correctly and if so wouldn't this mean this engine has the correct timing?
 
As well as the exhaust having loose baffles in the muffler(s), the exhaust can also move more under load, contacting the parking brake cable, sub frame, and the bends that go over the rear axle can bang against the frame rails. All of those things are less likely to show up when revving in neutral, but when the engine twists under load, things move a lot, and when not properly positioned can bump against stuff.

Look for areas on the exhaust and/or frame areas that are rubbed clean...
 
The sound while driving sounds like it starts at the rear of the engine but is louder under the car behind the front seats. Ive looked it over underneath and can't find anything that stands out. I'll check again in the morning when she's cold.

Now that i think of it the sounds reminds me a bit of my old vw bug i had 25 years ago when you would lug the engine real low rpm in to high of a gear.......
 
As well as the exhaust having loose baffles in the muffler(s), the exhaust can also move more under load, contacting the parking brake cable, sub frame, and the bends that go over the rear axle can bang against the frame rails. All of those things are less likely to show up when revving in neutral, but when the engine twists under load, things move a lot, and when not properly positioned can bump against stuff.

Look for areas on the exhaust and/or frame areas that are rubbed clean...

Exhaust tubing that is walking usually does so because a motor mount is bad. Also check the rubber snubber mounted above the third member, if it has fallen off, you will get some noise from the rear end contacting the snubber mount metal on metal under full throttle.

Dave
 
I’m assuming you have a 8 3/4 rear end with a factory pinion snubber mounted on the top of your pumpkin .when you punch your car hard from a stop the snubber turns upward with the rear end and hits your floor boards and stops your rear end from turning upwards from torque . I know this noise because my car does it when I hammer it hard from a stand still . I attached a few pictures to help explain what I’m talking about . To to truly diagnose the issue , you would have to record the noise in a video or something and post it. This noise is more of a thumping noise on the floor boards coming from the back end of the car only when you punch it from a stop. You can look under the car for a shiny or worn spot on the floor boards where the rubber bumper of the snubber was hitting it just above the rear end . If you find that spot of contact , that’s probably your noise. Good luck
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Checked the timing the best I know how at this point so Ill describe what I did... Hooked the timing light to the battery and the #1 cylinder,diver side front spark plug wire. Started engine, idles at about 575-600rpm. Shine the light on the degree marks on the from of the engine and it was before the 10* mark. I then realized I had a button on my timing light that would change the degrees. I pressed it until it read 11* and was dead on at the 0*mark on the engine. I then had my son raise the rpm to 3500 and I adjusted the light again until it was back on 0* at the engine and the timing light read 36*. I did the same thing but this time disconnected the vacuum hose from the carb to the distributor and got the same results 36*. Did I do this correctly and if so wouldn't this mean this engine has the correct timing?

If the emission stickers are still on the car if should give you the correct timing settings. Most '67 Chryslers with either 440 should be set at 12 1/2 degrees base timing. That would be with the engine set at about 650-700 rpms with the vacuum advance disconnected and plugged. The timing mark on the balancer is top dead center and the advance scale on the timing cover gives the degrees of advance. The scale is usually marked with a "V" cut that is deeper than the others which represents the correct timing setting. Start there, today's fuels sometimes need some compensating with slightly lower advance settings to stop the engine from pinging. The 36 degree reading is total advance from the vacuum advance and the centrifical advance at 3500 rpms, which would appear to be about normal. You should disable the total advance feature when setting base timing.

Dave
 
Take a video and post it. Way too many possibilities here. Check the specs on your engine to see if the timing is close. Also see if you were supposed to disconnect the vacuum advance while checking.
 
Went out to check the distributor vacuum assist, pulled the hose off the carb and tried to create some suction by using my mouth... sorry no vacuum gun yet. There was no vacuum created. I can blow air straight through it, so I guess thats not working either.... But as I was taking off the distributor cap, I found 2 loose wires that fell off. I reconnected them as was hoping that was the problem. Nope, but it does have a lot more power now. Guess i was running on only 6 cylinders. This car is so low, its new to me by the way, I can't really get under it to see very well. Ill have to put it on jacks to be able to see anything underneath it. I took it out for a quick drive and recorded the sound. Definitely seems to be more in the rear of the car area, like under the back seat. trying to upload the video to youtube now...
 
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